The zero-field parameters for the lowest n-pi* triplet state of pyrazine are determined using optical detection of the magnetic resonance in zero magnetic field. The values thus obtained are D = +/- 0.33923 +/- 0.00002 cm(-1) and E = +/- 0.00719 +/- 0.00002 cm(-1). The hyperfine splittings due to the mtrogen and hydrogen nuclei are discussed.